1). Field of the Invention
The present invention relates generally to agricultural implements and, more specifically, to a height sensing shoe arrangement for an automatic height control on an implement or harvester.
2). Related Art
Harvesters such as cotton pickers include row units having height sensing shoes for automatic height adjustment to maintain an optimum unit operating position during harvesting. Each shoe is pivotally connected to an associated unit for rocking about an axis transverse to the forward direction of travel so a small portion of the shoe remains in contact with the soil. A rod is connected between the shoe and a valve or switch structure which responds to pivoting of the shoe to operate a row unit hydraulic lift to raise and lower the unit as necessary to maintain the optimum position. Often the harvester is operated in crusted or uneven field conditions, and the shoe rapidly pivots up and down as the harvester moves over closely spaced undulations in the soil surface. Such pivoting causes a corresponding rapid and undesirable movement of the valve or switch structure thereby inputting a less than optimum control signal to the hydraulic lift system. The rapid shoe pivoting caused by the small contact area riding over the soil surface increases forces and wear in the control system and in the hydraulic lift system. Although averaging to reduce rapid row unit movement can be accomplished electronically or hydraulically, the increase in system cost, complexity and response time usually makes such a fix undesirable. The small soil contact area on the shoe also results in rapid wear which necessitates time-consuming shoe replacements.